The following invention relates to an assembly of a drilling needle in a drill chuck for coupling with a drive device as well as to the drilling needle itself.
A “drill chuck” refers in this context to a clamping device that receives, on a tool, the employed tool such as a drill or here a drilling needle.
A frequently used drill chuck is a three-jaw chuck in which the part to be secured is clamped between three clamping jaws; this provides the advantage of a good centering action of the secured employed tool (e.g., drilling needle). Greater clamping forces can be achieved by gear ring drill chucks that can be tightened by means of a drill chuck key. Moreover, drill chucks for masonry drill bits on percussion drills are known that do not clamp the tool by friction but transmit torque by means of form fit and in this way enable axial movement of the tool.
Special drill chucks are also used in devices for drilling resistance measurement. With such drilling resistance measurement devices that employ a thin drilling needle, objects into which such a needle can be drilled can be examined in their interior with regard to their condition or their quality without destroying or significantly damaging the object. The drilling needle must be replaced regularly in order to provide reliable measured data.
In order to simplify replacement, DE 10 2011 103 636 A1 discloses a needle replacement cartridge and a drilling measurement device that is provided with this needle replacement cartridge. In this context, the drilling needle is secured fixedly on one end of a telescoping pipe while at the opposite end of the telescoping pipe a docking device is arranged with which the telescoping pipe and thus the drilling needle is coupled to a drive. This docking device comprises a magnetic holder that is connected releasably with the docking end of the telescoping pipe and comprises a coupling device, such as a claw coupling, snap-on coupling or a bayonet closure in order to transmit the torque from the drive device of the drilling measurement device to the telescoping pipe. The magnetic holder which is embodied as a hollow cylinder functions as a type of drill chuck and serves for axial centering of the telescoping pipe so that the drilling needle is aligned with the drive axis.
Usually, drilling needles are provided at their fastening section with a mechanical clamping device or a thread in order to be screwed to the drilling needle receptacle. Therefore, the drilling needles can be rotated only in one direction without becoming detached. Moreover, breakage of the drilling needle happens frequently particularly in the area of the drilling needle receptacle.
Clamping of a drilling needle with several clamping bodies is dealt with in DE 100 31 339 A1.